Medical device manufacturers are continually increasing the processing capabilities of patient monitors, specifically of patient monitors that process signals based on attenuation of light by patient tissue. In general, such patient monitoring systems include one or more optical sensors that irradiate tissue of a patient and one or more photodetectors that detect the radiation after attenuation thereof by the tissue. The sensor communicates the detected signal to a patient monitor, where the monitor often removes noise and preprocesses the signal. Advanced signal processors then perform time domain and/or frequency domain processing to determine measurements of blood constituents and other physiological parameters of the patient.
Manufacturers have advanced basic pulse oximeters that determine measurements for blood oxygen saturation (“SpO2”), pulse rate (“PR”) and pethysmographic information, to read-through-motion oximeters, to co-oximeters that determine measurements of many constituents of circulating blood. For example, Masimo Corporation of Irvine Calif. (“Masimo”) manufactures pulse oximetry systems including Masimo SET® low noise optical sensors and read through motion pulse oximetry monitors for measuring Sp02, PR, perfusion index (“PI”) and others. Masimo sensors include any of LNOP®, LNCS®, SofTouch™ and Blue™ adhesive or reusable sensors. Masimo oximetry monitors include any of Rad-8®, Rad-5®, Rad®-5v or SatShare® monitors.
Many innovations improving the measurement of blood constituents are described in at least U.S. Pat. Nos. 6,770,028; 6,658,276; 6,157,850; 6,002,952; 5,769,785 and 5,758,644, which are assigned to Masimo and are incorporated by reference herein. Corresponding low noise optical sensors are disclosed in at least U.S. Pat. Nos. 6,985,764; 6,088,607; 5,782,757 and 5,638,818, assigned to Masimo and incorporated by reference herein.
Masimo also manufactures more advanced co-oximeters including Masimo Rainbow® SET, which provides measurements in addition to Sp02, such as total hemoglobin (SpHb™), oxygen content (SpCO™), methemoglobin (SpMet®), carboxyhemoglobin (SpCO®) and PVI®. Advanced blood parameter sensors include Masimo Rainbow® adhesive, ReSposable™ and reusable sensors. Masimo's advanced blood parameter monitors include Masimo Radical-7™, Rad-87™, and Rad-57™ monitors as well as Pronto and Pronto-7 spot check monitors.
Innovations relating to these more advanced blood parameter measurement systems are described in at least U.S. Pat. Nos. 7,647,083; 7,729,733; U.S. Pat. Pub. Nos. 2006/0211925; and 2006/0238358, assigned to Cercacor Laboratories of Irvine, Calif. (“Cercacor”) and incorporated by reference herein.
Such advanced pulse oximeters, low noise sensors and advanced blood parameter systems have gained rapid acceptance in a wide variety of medical applications, including surgical wards, intensive care and neonatal units, general wards, home care, physical training, and virtually all types of monitoring scenarios.